Lamp holder



June 8, 1965 R. A. BRIDWELL LAMP HOLDER 3 Sheets-Sheet 1 Filed Nov. 2,1962 iin@ June 8, 1965 R. A. BRIDWELL.

LAMP HOLDER 3 Sheets-Sheet 2 Filed NOV. 2, 1962 June 8, 1965 R. A.BRlDwl-:LL

LAMP HOLDER 3 Sheets-Sheet 5 Filed Nov. 2, 1962 United States Patent O3,l88,459 LAMP HOLDER Robert A. Bridwell, Lynwood, Calif., assigner toNorthrop Corporation, Beverly Hills, Calif., a corporation of CaliforniaFiled Nov. 2, 1962, Ser. No. 235,066 l Claims. (Cl. 24d-a7) 'My presentinvention relates to electric lamps, and more particularly to a snap-inlamp holder for high intensi-ty qu artz lamps.

A serious problem with the industrial application ofl high-temperaturequartz lamps of the tubular type used, ttor example, in enamel baking,material drying, heat treatment of metal, metal-to-metal brazing, etc.,is .the high incidence of Vfail-ure of such lamps after a relativelyshort operating life due to rap-id deterioration and destruction of thelam-p end-seals and terminals which are exposed to the high operatingtemperatures. Some lamps burn at 1000 watts per inch of lamp length. A10" lamp, for example, operates with as high as 10,000 watts of power.

Presently available reflector fixtures are usually provided withVentilating openings intended to .permit the circulation of ambient airaround the lamps for cooling purposes.

While such openings generally satisfy cooling requirements `forilluminating lam-ps, it is not possible to reduce the exposureenvironment of the vulnerable parts of high temperature infrared lampsto nondestructi-ve temperatures with such openings.

Moreover, it is found that whatever cooling is achieved with theopenings in conventional reflector lfixtures also tends to reduce thetemperature of the lamp envelope as Well as the lamp terminal partssubject to deterioration and failure. It is highly desirable, where heatis the pri- 'hx-tures available is the undue complexity and high initialcost of the units, Substantial disassembly of conventional reflectorfixtures is usually required to replace a burnt-out lamp. Thus lampreplacement, up to the time of my invention of the lamp holder describedand claimed herein, has :been unnecessarily expensive andtime-consuming, particularly where large banks of lamps `are employed.

In view of the present state-of-the art, it is an object orf myinvention to provide a lamp holder having means for accommodating ahighly efiicient cooling system.

It is another object of my invention to provide a snapin lamp holder andreflector fixture combination that is universally suitable for mostradiant heating applications.

It is a further object of my invention to provide a relativelyinexpensive snap-in lamp holder that is individually, quickly, andeasily removable without disassembly of the reflector assembly.

It is a still further object of this invention to provide a lamp holderand reflector fixture that Iwill safely permit watt densities to beincreased by a substantial margin over the tightest spacing of lamps nowpossible with current infrared lamp xtures.

Yet'another object is to provide a heat lamp end holder havingtheelectrical contact elements covered and protected by lan insulatingenclosure.

Briefly, the snap-in lamp holder of my present invention comprises abody of material having good dielectric and heat-dissipatingcharacteristics, the body having a lamp socket therein provided with asystem of interconnected, internal forced-air passages within whichl thelamp end seal is supported and fastened solely by the lamp terminalwire.i

The reflector fixture of my invention comprises a reflector panel thatis susceptible of many forms and shapes having means =for mounting thelamp holder used in combination therewith in a number of possible lamparrangements.

Other objects and advantages inherent in the lamp holder and reflectorfixture of my invention will readily be seen by referenceY to `theappended detailed specification and drawings wherein:

FIGURE 1 is a diagrammatic plan view showing lamp holders made accordingto my present invention in combination with .a reflector fixture.

FIGURE 2 is a diagrammatic end view of the reflector assembly and lampholders viewed as indicated by the line 2 2 of FIGURE l.

FIGURE 3 is an enlarged fragmentary View in crosssection, taken asindica-ted by the line 3-3 of FIGURE l, showing the construction of thelamp holder and end portion of the reflector assembly shown in FIGURES land 2.

FIGURE 4 is a diagrammatic view in cross-section showing theconstruction of the lamp holder and end portion of a different reflectorassembly.

FIGURE 5 is' a diagrammatic cross-sectional view taken on line 5-5 ofFIGURE 4.

FIGURE 6 is a diagrammatic three-quarter view of a circularly Iformedreflector fixture and lamp.

FIGURE 7 is a diagrammatic three-quarter view in perspective of anotherform the lamp holder of my present invention may take with portions cutaway to show the interior adapted tol hold two lamps.

FIGURE 8 is a diagrammatic three-quarter view in perspective showingstillV another embodiment of my lamp holder with portions thereof cutaway to show the interior adapted to hold llamps in tandem.

FIGURE 9 is a diagrammatic end view of a typical lamp holder for alive-lamp combination.

In FIGURES l and' 2 a reflector fixture 5 is shown, formed of a sheet ofhigh-temperature resistant material having a highly polished surface 6preferably gold-fired with a ceramic material in the usual manner. Thesize and shape of the reflector is of course governed by the size andnumber of lamps to be accommodated.

As illustrated, the reflector 5 is generally rectangular to accommodatea bank of elongated infrared lamps of a well-knownv model and makeemploying an elongated tubular envelope 8 of quartz, the envelope 8being pinched or flattened at each end and wrapped with foil or thinsheet material, such as Nichrome, lnconel, or like high temperatureresistant metal, to form an end seal 9.

TheI lamp filament assembly (not shown) is supported in the envelope 8'and extends coaxially therethrough from end to end, each end beingconnected to a flexible stranded terminal wire it] the inner end ofwhich is mounted and sealed within the end seal 9. The outer end of theterminal wire 10 extends outside of the end seal 9 to be electricallyconnected as will be described below.

Mounted at each end of the reflector 5 are a number ol' lamp holders l2within which the lamps are supportedy a desired distance over thereflector surface 6.

InFIGUR'E 3 the construction of a typical lamp holder holder l2 is shownin detail. The body 13 of lamp holder 12 is molded or otherwise formedof a material having satisfactory thermal shock resistantcharacteristics, such as hydrous aluminum silicate for example. Theinterior of the body 13 is hollowed out to form a lamp socket 14, havingan opening 15 at one end thereof, within which the end seal 9 of thelamp can be enclosed. The dimensions of socket 14 are purposely madesubstantially larger than the dimensions of the end seal 9 so that noportion of the end seal surface contacts any surface of the socket 14.

Near the closed end 16 of socket 14 a threaded bore 17 is provided, thebore 17 opening at one end thereof in the bottom of socket 14, the otherend of the bore opening at the bottom of body 13.` v Y i An externallythreaded hollow terminal stud 20 is threadably mounted in bore 17, thestud 20 preferably being made of brass or other material havingsatisfactory electrical conducting properties.

The -opening at the upper end of stud 211 can be coterminus with theopening of bore 17 in socket 14, and internally flared or chamfered foreasier insertion of lamp terminal wire 11i thereinto.

Adjacent opening of socket 14, a second bore 21 is provided to exhaustheated air from socket 14.

In this holder, as well as the subsequent holders to be describedherein, the diameters of the air passages should be slightly greaterthan the Width of the socket supplied thereby.

Near the bottom of body 13, another bore 23 is provided extending in thesame direction as socket 14, andr intersecting bore passages 21 and 17,bore 23 having an opening 24 at the exterior of body 13 and an openingZ5 in the wall of threaded bore 17.

The exterior of the hollow terminal stud 2li preferably is threadedabout half of its length, and a lateral threaded bore 27 is drilledthrough the wall thereof to accommodate a set screw 28 mounted in bore23 adjacent the inner opening 25 thereof.

When inserted, the lamp terminal Wire 10 is entirely recessed within theinterior of hollow stud and tightly clamped in lamp-supporting positiontherein by set screw 2S, as shown. It is reiterated that terminalwireil() is adjustably clamped within the interior of the hollowterminal stud so that no portion of lamp end seal 9 is Y4 side thereofto open in' each respective receptacle pocket 46. A detent ball 51 andback-up spring SZ are provided in each bore Si), a single typicalexample being shown,

permitted to come in contact with the interior surface of socket 14. Thesize and relative rigidity of the wire 10v helps make this possible.

The remaining portion of the exterior surface of terminal stud 20, belowthe threaded portion, is purposely left Unthreaded for easy insertioninto and withdrawal from a -suitable snap-in receptacle to be describedbelow.

The holder 12 is thus seen to cover and enclose the otherwise exposedelectrical contact surfaces of the end seal 9 and terminal Wire 10, toprotect against accidental shock to personnel and damage to equipment byinadvertent short circuiting or grounding.

For support of the lamp holders 12 at each end of reflector 5, amounting block 30 is attached in any convenient manner, the block 3i)being made of material having good heat and electrical insulatingcharacteristics.

In FIGURE 3, the reiiector 5 is formed at each end with a double ange31, the block 30 being attached by a bolt 32 provided therein andextending through a spacer 33 and a hole 34 in ange 31 and fastenedthereto with aY nut 35.

Mounted in block 3d, a receptacle assemblyV 40 is provided, comprising aflat metal plate that defines a bus bar 41 along one edge of which anumber of tubular receptacles 42 are fastened in spaced relation forsupport, the bar 41 and receptacles 42 preferably being made of metalhaving satisfactory electrical conducting properties such as stainlesssteel for example.

A terminal post 43, made of highly conductive material, is mounted andfastened to bus bar and is extended perpendicularly 'therefrom throughVa bore 44 drilled through block 30. Y

VTo recess and support the receptacles 42 in block 361,' correspondingpockets 4e are provided, each of the pockets 46 intersecting a main 'airpassage defined by bore 47 extending lengthwise through block 50. Theopen end 4S of bore 47 can be plugged in any convenient manner.

As best shown in FIGURE 3, ball detent bores 5t) are provided in` block30, extending into block Stifrorn one .the ball 51 extending through alateral bore sfprovided in the wall of receptacle 42, to engage anexternal c1rcumferential groove 55 that extends around terminal stud 2i)near its lower end. The external opening around bore S3 in the wall ofreceptacle 42 should be chamfered to permit detent ball 51 to engage4the entire surface of groove 55.

Each detent ball 51 and back-up spring 52 is retained in its respectivebore 50 in any well known manner, a threaded plug 57 being shown in thepresent example.

Cool air is supplied to lamp socket 14 through a nipple 5?; fitted intoa short bore 59 in'the bottom of block 3@ that opens into bore passage47, the nipple 53 being connected to a conduit e@ carrying cool air froma source V(not shown) provided therefor. An air blower may be connectedto the far end of the conduit 611. Y

The cool air flows through air passage 47 and passes though terminalstud Z0 and into socket 14to be circulated freely over the entire endseal 9 surface. The heated air is exhausted from socket 14 throughopening 15 and y air passages 21 and 23. Appreciable cooling of the lampenvelope S is avoided, while the end seal is continuously subjected to afresh supply of cool air to effectively maintain the end sealenvironment at a non-destructive temperature. f

Lamp power is supplied Vby connecting post 43 to a source ofelectricitytnot shown) provided therefor. The electricity is conductedthrough bus bar 41, receptacles 42 and terminal studs 21? to the lampterminal wire 111 in the conventional manner.

A tool stot 65 can be provided in the holder body 13,

if desired, by which means a suitable prying tool or lever i may beinserted for easier disengagement of the lamp holder from itsreceptacle.

Another 'form the reiiector assembly may take is shown in FIGURES 4 and5 wherein a reiiector 7d, having a highly polished surface 71 finishedwith a gold tired ceramic coat, is joggled at each end to provide amounting iange 73 to support a quantity of holder and receptacleassemblies, only a fragmentary portion of one end being shown.

As many adaptor holes '75 as are needed are drilled in the mountingharige 73 at each end of reiiector 7i), and an equal number of openings76 are provided in the end leg of the reflector to pass exhaust airtherethrough.

Individual receptacle assemblies are provided for each lamp holder, atypical assembly being shown in detail in FIGURE 4.

The lamp holder l77 is identical in construction to the holder 12 shownin FIGURES 1 3, comprising a body i8 of thermal shock resistant ceramicmaterial having a socket 79 in which the end seal 8@ of a lamp d1 ishoused, the end seal Sti being cooled by cool air supplied through airpassage 33.

The hollow terminal stud of the holder is threadably mounted in the airsupply passage 83, the stud 85 having external threads S6 on theupperportion thereof, the lower portion 37 being unthreaded with an externalcircumferential groove 8d adjacent its lower end.

The terminal wire 911 of the lamp 81 is inserted into the interior ofthe hollow terminal stud 8S and clamped therein with va set screw 91 inlamp supporting position so` that no part of the end seal 811 contactsany surface of the holder socket '79 asin the holderr12 of FIGURES 1-3.

The receptacle assembly comprises a hollow male 95 and female 96 ceramicinsulator coupled together on each side of mounting iiange 73 by apartiaily externally threaded `hollow core bolt 97. A circumferentialflange 9S vis provided around the upper opening of core boit 97, thediameter of the lower portion thereof being reduced to denne a nipple 99over which an air supply hose 1th) is connected to carry cool air from asource (not shown) provided therefor.

A pair of opposed key slots mi are cut through the wall of core bolt 97in which a U-shaped spring key 102, preferably made of piano wire, isretained, the legs of spring key 102 extending into the interior of corebolt through the slots lill on each side of the bolt to engage thecircumferential groove 83 of terminal stud 85.

Lamp power is Vsupplied to the terminal wire 9i) in the usual manner, asolderless terminal itl@ retained on core bolt by a washer 163 and nut11i? being shown for example.

Thus any number of lamp holders 77 required may be mounted on themounting ilange 73, each holder 77 being separately connected to asource of electricity, or commonly connected to a bus bar (not shown) inthe conventional manner;

The path of forced air through the hollow terminal stud 85 into socketiii is traced by arrows wherein it can be seen that substantially all ofthe lixture parts and the entire surface of the lamp end seal are cooledby the air.

, The air is supplied by hose 1%, being blown or otherwise forced from asupply which can be refrigerated in any convenient manner if desired.

it will be readily seen that the reflector tlxture of my resentinvention can be designed in any practical size to hold as many lamps asmay be needed forany given application. Each lamp end seal is, inessence, individually, separately and eiiiciently cooled.

The lamp holder and reflector xture of my invention have many possibleforms, another form being shown in FIGURE 6 wherein a twopart reilectorsurface 111, 112 is made of any suitable high temperature resistantrnaterial and assembled in a circular shape, the lamp holders 77 beingmounted on the refiector in substantially the same manner as describedabove and shown in FGURE 4. The lamp holder 77 and receptacle assemblyof PEG- URE 4 are highly suitable for the circularly shaped reileetor,the receptacle assemblies being mounted in adaptor holescircumferentially spaced adjacent the upper and lower edges of thereflector.

The lamp holders can be connected to a power supply individually orcommonly through a bus bar, suchconnections being omitted in the drawingas they are deemed to be weil known in the art.

Cool air is supplied to each holder by tubes 11e tted over the ends oftheir respective hollow terminal studs, the other ends of the tubesbeing connected to one of a pair of main air conduits or manifolds 117and 11h carrying cool air from a source (not shown) thereof.

While thus far I have shown the lamp holder of my present inventionadapted to hold a single lamp, a modified. embodiment of the holder isshown in FiGURE 7 wherein a lamp holder 119 havini7 a body 12d isprolvided with. two sockets 121 and itlseparated by a web the holdersdescribed above, being equipped with a single terminal stud 12S, setscrew bore 129 and set screw 130, and tool slot 131, all constructed andassembled in the same manner.

Y Another embodiment of holder has been made wherein three socket spacesare provided in one holder in a generally triangular arrangement, twospaced closely on one level and one centered between these two butslightly above or below them. Thus the generated heat is yfurtherconcentrated, or as termed previously, the watt density is furtherincreased.

ln certain installations it may be desired to mount banks of lamps inseries, i.e., end-to-end relationship, or in la long line whereinatandem arrangement of the lamps is necessary,

Such an arrangement can be achieved with still another modified form ofmy lamp holder 1.4i?v and shown in FlG- URE 8 wherein the holder body141 is provided with canted sockets 142 and 143 which extend entirelythrough the body 141, being open at each end thereof.

As in thecase of the holder 119 of FIGURE 7, the air passages 145, 145and 147 extend through the thinnest section of the web 144 and thus openinto each socket 142 and 143, one additional passage 147 being providedover those in the` previously described holder 119.

The holder body 141 isprovided with a terminal stud 15d, set screw bore151 and set screw 152, and tool slots 153 at each end, all constructedand arranged the same as in the yholders of the previous gures.

The receptacles (not shown) for holders 119 and 14E-t) canbe of the typedescribed above and shown in FIG- URES 1-5.

It will be immediately apparent that combinations of holders can beemployed to provide predetermined heat concentration, one of a number ofsuch combinations being shown in the end view of FGURE 9 wherein asingle lamp holder mounted on a reflector 161 is flanked with doublelamp holders 162. on each Side, to provide a live lamp combination.

Thus, the holder of my invention gives rise to enumerable modiiicationswherein even threee or more lamps can be supported on a reilector of anygiven size and shape, all such` modifications. and combinations beingdeemed to fall within the spirit and scope of my invention as recited inthe appended claims.

I claim:

1. A holder for the support and temperature control of each end of atubular lamp-having at each end thereof an end seal and terminal wire,comprising:

(a) a body of dielectric material completely enclosing said end seal andterminal wire,

(b) means deiining an open socket in said body to recess the end sealand terminal wire of said lamp,

(c) means defining an air supply passage in said body openingsubstantially perpendicular into the side of said socket,

(d) a hollow terminal stud securely mounted in said supply passage andhaving a projecting end portion for fitting into a receptacle, said lampterminal wire extending from said socket into said stud with substantialspace around said wire for cooling air how through said stud,

(e) screw fastening means in the side of said supply passage and throughsaid stud to clamp said terminal wire in the interior of said stud,

(f) a mounting block of electrical insulating material,

(g) an electrical conducting receptacle attached to said block andhaving resilient retention means adapted to engage saidprojecting endportion for supporting said holder body,

(h) means defining an additional air passage in said block tocommunicate with said hollow terminal stud,

(i) an air inletconnected to said additionalair passage,

and

(j) electrical connector means secured to said recepftacle forconnecting said receptacle to a source of electric power for operationof said lamp.

2. Apparatus in accordance with claim l wherein said socket is largerthan said end seal to provide air circulation space around said endseal, and including means defining an air exhaust passage in said bodyconnecting the interior of said socket with ambient outside air.

3. A dual lamp holder for one end of a pair of lamps each having aliattened rectangular end seal and a terminal Wire, comprising:

(a) a body of dielectric material,

(b) a pair of side-by-side, open end socket spaces in said bodygenerally tting over said end seals, re spectively, but substantiallylarger around than said end seals, said socket spaces being slantedtoward each other in cross section to form two sides of an open-bottomedV, p

(c) a single air supply passage in said body opening substantiallyperpendicular into both said sockets at the lower sides thereof,

(d) a hollow terminal stud mounted in said supply passage and having aprojecting plug end portion for electrically connecting into a mountingreceptacle, and

(e) fastening means in the side of said stud for securing the terminalwires of said lamps therein, the hollow interior of said stud beingsubstantially larger than the two terminal wires whereby cooling air cancirculate through said hollow stud and said socket spaces around saidlamp end seals. t

4. A double-ended lamp holder for holding one end of each of twoend-to-end lamps each having an end seal and a terminal wire,comprising:

(a) a body of dielectric material, Y

(b) a continuous socket space of uniform diameter through said body longenough to contain one lamp end seal inserted from one end of said spaceand a second lamp end seal inserted from the other end of said space,said space being of suiiicient diameter to provide a clearance aroundsaid end seals,

(c) an air supply passage leading into said socket space with itsopening adjacent to said lamp end seals,

(d) a single hollow terminal stud mounted in said passage and having aprojecting snap-in portion for electrical connection in a mountingreceptacle, and

(e) fastening means in the side of said stud for locking the terminalwires f said lamps therein, the hollow interior of said stud beingsubstantially larger in diameter than the two terminal wires wherebycooling air can ow through said stud and said socket spacetaround saidlamp end seals.

5. Apparatus in accordance with claim 4 including an air exhaust passagethrough said body on each opposite side of said supply passage, saidexhaust passages Vconnecting the respective ends of the interior of saidsocket space with ambient outside air.

6. Apparatus in accordance with claim 1 including a plurality of saidbodies, terminal studs and receptacles,

said block being large enough to vcontain said plurality of receptacles,air manifold means interconnecting the open ends of all said hollowterminal studs to a single outer air supply connection, and electricalbus means connecting all said receptacles for one end of a plurality oflamps to a single electrical supply connecten 7. A reilector assemblyfor elongated tubular lamps that have an end seal and terminal wire, ateach end thereof, comprising:

(a) means dening a reflecting surface,

(b) means at each end of said reflecting surface to enclose and supportrespective ends of said lamps, said enclosure and support meanscomprising (l) an electrical conductive receptacle having air passagemeans therethrough, (2) means including insulated mounting meansattaching said receptacle to said reflecting surface,

(3) a hollow snap-in stud removably mounted in said receptacle,

(4) a lamp end holder of dielectric material having at least one socketcavity therein to receive and enclose a lamp end seal, said cavity beingsubstantially larger than said end seal to allow forced air to owtherearound, said stud attached in said holder with its inner end incommunication with said cavity near the terminal wire from said endseal,

(5) means in said stud for locking said terminal wire therein so thatsaid terminal wire provides the sole support for its associated lamp endin said cavity, the hollow interior of said stud being large enough tocarry adequate cooling air ow around and past said wire,

(c) cooling air supply conduit means connected to said air passage ineach said receptacle for liow through said stud and cavity and aroundeach said lamp end seal, and

(d) means connected to each said receptacle fortconducting lampoperating current thereto.

8. A holder for the support and temperature control `of each end ofatubular lamp having at each end thereof and end seal and terminal wire,comprising:

(a) a body of dielectric material,

(b) a socket in said body and having an opening at one end of said bodyto receive and completely enclose at least a major portion of said endseal of said lamp, the inside dimensions of said socket being largerthan said end seal to provide a clearance therebetween,

(c) an air supply passage having an opening in said socket adjacent tosaid end seal,

(d) a hollow stud to receive andV retain said terminal wire and mountedin said air supply passage to dene a conduit to direct forced air intosaid socket for circulation around said end seal,

(e) screw means to fasten said terminal wire in the interior of saidhollow stud,

(f) and means adapting the free end of said stud for connection with asource of electricity and forced air.

9. A holder for the support and temperature control of each end of atubular lamp having at each end thereof an end seal and terminal wire,comprising:

(a) a body of dielectric material,

, (b) a socket in said body and having an opening at one end thereof toreceive and surround a major portion of said end seal of said lamp, thedimensions of said socket being larger than said end seal to provide aclearance therebetween,

(c) an air supply passage leading into said body and opening in saidsocket adjacent toV said end seal,

(d) a hollow stud to receive and retain said terminal wire and mountedin said air supply passage to de-Y ne a conduit to direct forced airinto said socket for circulation around said end seal.

(e) screw means mounted in the wall of said stud to y fasten saidterminal wire in the interior thereof,

(f) and snap-in means for connecting saidstud to a supporting base,source of electricity, and a source of forced air. Y t

l0. A holder for the support and temperature control of each end of atubular lamp having at each end thereof an end seal and terminal wire,comprising:

(a) abody of dielectric material,

(b) a socket in said body and having an opening at one end of said bodyto receive and enclose the end seal of said lamp, the inside dimensionsof said socket being relatively larger than said end seal to providearclearan'ce therebetween, I

(c)` an air supply passage in a wall of. said body and 9 having anopening in said socket adjacent to said end seal,

(d) an exhaust passage leading from said socket'1 and having an openingexterior of said body,

(e) a hollow stud mounted in said air supply passagey to receive andretain said terminal Wire, the interior of said terminal vwire retainingstud further defining a conduit to direct air into said socket forcirculation around said end seal,

(f) screws means to fasten said terminal wire in the interior of saidhollow stud,

(g) and snap-in means for adapting said stud for installation in thereceptacle of a supporting base, said base providing connections with asource of electricity, and a source of forced air.

References Cited bythe Examiner UNITED STATES PATENTS NORTON ANSI-IER,Primary Examiner.

8. A HOLDER FOR THE SUPPORT AND TEMPERATURE CONTROL OF EACH END OF A TUBULAR LAMP HAVING AT EACH END THEREOF AND END SEAL AND TERMINAL WIRE, COMPRISING: (A) A BODY OF DIELECTRIC MATERIAL, (B) A SOCKET IN SAID BODY AND HAVING AN OPENING AT ONE END OF SAID BODY TO RECEIVE AND COMPLETELY ENCLOSE AT LEAST A MAJOR PORTION OF SAID END SEAL OF SAID LAMP, THE INSIDE DIMENSIONS OF SAID SOCKET BEING LARGER THAN SAID END SEAL TO PROVIDE A CLEARANCE THEREBETWEEN, (C) AN AIR SUPPLY PASSAGE HAVING AN OPENING IN SAID SOCKET ADJACENT TO SAID END SEAL, (D) A HOLLOW STUD TO RECEIVE AND RETAIN SAID TERMINAL WIRE AND MOUNTED IN SAID AIR SUPPLY PASSAGE TO DEFINE A CONDUIT TO DIRECT FORCED AIR INTO SAID SOCKET FOR CIRCULATION AROUND SAID END SEAL, (E) SCREW MEANS TO FASTEN SAID TERMINAL WIRE IN THE INTERIOR OF SAID HOLLOW STUD, (F) AND MEANS ADAPTING THE FREE END OF SAID STUD FOR CONNECTION WITH A SOURCE OF ELECTRICITY AND FORCED AIR. 